Code Smell 283 - Unresolved Meta Tags
Incomplete Meta Tags are Unprofessional
TL;DR: Incomplete or null meta tags break functionality and user experience.
Problems
Tags appear in output
Email texts include placeholders between human-readable text
Missed placeholders confuse users
Websites are rendered with strange characters
Null values trigger errors
Potential security injection vulnerabilities
Solutions
Validate meta tags
Assert completeness early
Avoid null values
Throw meaningful exceptions
Automate meta validation
Context
When you leave meta tags unfinished, such as {user_name} or {product_name}, they often sneak into your final output. Imagine sending an email that says, "Hi {user_name}, your order for {product_name} is ready."
It screams unprofessionalism and confuses users.
Null values worsen things by causing crashes or silent failures, leading to bad user experiences or broken processes.
You can avoid this by asserting completeness before rendering or sending.
When your code finds an incomplete meta tag or a null value, stop the process immediately and throw an exception.
Sample Code
Wrong
<?php
$emailBody = "Hello {user_name},
your order for {product_name} is confirmed.";
// You forget to make the replacements
sendEmail($emailBody);Right
<?php
$emailBody = "Hello {user_name},
your order for {product_name} is confirmed.";
if (strpos($emailBody, '{') !== false) {
throw new Exception(
"Incomplete meta tags found in email body.");
}
sendEmail($emailBody);Detection
[X] Automatic
You can detect this smell with automated tests or linters scanning unfinished placeholders ({} or similar patterns).
Tags
Fail Fast
Level
[X] Beginner
Why the Bijection Is Important
Your system must maintain a one-to-one mapping when representing user data with placeholders.
You break this mapping if your {user_name} placeholder exists but lacks a corresponding real name.
This causes errors, confusion, and a loss of trust in your application.
Ensuring bijection compliance avoids these issues.
AI Generation
AI tools sometimes introduce this smell when generating templates with placeholders but fail to substitute real data.
You must validate and complete all placeholders before using the output.
AI Detection
AI tools like linters or email rendering validators can detect unfinished meta tags if you configure them correctly.
Use these tools to automate meta-tag detection and reduce human error.
Try Them!
Remember: AI Assistants make lots of mistakes
Without Proper Instructions
With Specific Instructions
Conclusion
Incomplete meta tags are more than just sloppy—they're harmful. Validate tags, assert completeness, and throw exceptions when needed.
Handling meta tags carefully prevents errors and ensures a professional experience.
Relations
Code Smell 139 - Business Code in the User Interface
Code Smell 97 - Error Messages Without Empathy
More Info
Null: The Billion Dollar Mistake
Disclaimer
Code Smells are my opinion.
Credits
Photo by Tomas Martinez on Unsplash
The best error message is the one that never shows up.
Thomas Fuchs
Software Engineering Great Quotes
This article is part of the CodeSmell Series.